This invention relates to an electromagnetic brake which is selectively operable to retard a rotary member such as a cylindrical disc or shaft. More particularly, the invention relates to an electromagnetic brake of the type which includes a field shell having magnetic poles and supporting an electric coil. The coil comprises a multi-turn winding which preferably but not necessarily is wound on the spool of a bobbin molded of resiliently flexible material and having annular flanges at the ends of the spool.
When the coil is de-energized, a spring urges an armature away from the shell and into engagement with the rotating member. As an incident thereto, friction material on the outer face of the armature applies a retarding force to the rotating member. When energized, the coil produces magnetic flux which attracts the armature toward the poles and away from the rotating member so as to release the retarding force.